Slides in this set

Slide 1

Core Chemistry (C1)Topics:·Emulsifiers·Cooking and Chemical Change·Perfumes·Kinetic Theory·Solutions·Paints and Special Pigments·Polymers· Hydrocarbons; Alkanes and Alkenes·Fractional Distillation·Cracking and Hydrocarbon properties and bonds·Burning fuels…read more

Slide 2

EmulsifierAdditives make food last longer· Food colours ­ make the food look more appetising· Flavour enhancers ­ bring out the taste and smell of food without adding a flavour of their own· Antioxidants ­ help to preserve food Hydrophilic (likes water, hates oil) Hydrophobic (likes oil, hates water)Emulsifiers help oil and water mix(emulsion)When you add some emulsifier to oil and water, the oil forms droplets surrounded by a coating of the emulsifier with the hydrophilic part facing outwards. Other oil droplets get repelled by the hydrophilic part of the emulsifier whilst any water molecules latch on so the emulsion doesn't separate out. Key Words: Solution: a mixture of its solute and solvent that does not separate out Solute: the substance being dissolved Solvent: the liquid it's dissolving in Soluble: it will dissolve Insoluble: it won't dissolve Solubility: a measure of how much will dissolve…read more

Slide 3

Cooking and Chemical Change Some foods need to be cooked e.g. boiling, grilling, frying etc...1) Better taste/texture2) Easier to digest3) Harmful microbes are killed (from high temperatures)4) Some foods such as kidney beans contain poison when rawCooking can cause chemical changes;e.g. Eggs and meat ­ good sources of protein, protein molecules change shape when heated. The energy from cooking breaks some of the chemical bonds in the protein allowing the molecule to take a different shape. The food also gets a more edible texture. This change is irreversible and is called denaturing.e.g. Potatoes ­ potatoes are plants meaning each potato is surrounded by a rigid cell wall made of cellulose. Humans cannot digest cellulose. Cooking the potato ruptures the cell walls. It makes the starch grains inside the cell swell up and spread out. These changes make the potato softer and more flexible and also much easier to digest. 2NAHCO NaCO + CO + HO…read more

Slide 4

PerfumesEsters are made by etherification:Acid + Alcohol = Ester + WaterPerfumes need certain properties...Easily Evaporates ­ So the perfume particles can reach the noseNon- Toxic ­ so it doesn't poison youDoesn't react with water ­ so it doesn't react with the water in your sweatDoesn't irritate the skin ­ so you don't get a rash/burnInsoluble in water ­ so it doesn't wash off every time you get wetto make an ester... Mix 10cm³ of a carboxylic acid e.g. ethanoic acid with 10cm³ of an alcohol such as ethanol. Add 1cm³ of concentrated sulphuric acid to this mixture, warm gently for about 5 minutes. Add the mixture to 150cm³ of sodium carbonate solution(to neutralise the acids) and smell carefully. A fruity smell should be the result.…read more

Slide 5

Kinetic Theory ­ Forces between ParticlesSolids: strong forces of attraction between the particles. If you heat the solid and give the particles more energy eventually it will melt and become a liquidLiquids: some forces of attraction between the particles. If you heat the liquid eventually it will boil and become a gasGases: no forces of attraction between the particles. The hotter the gas gets the faster they move, it expands when heated or the pressure increases.Volatity...Perfumes need to be quite volatile so they can evaporate enough to be smelt. The particles in the perfume have very weak forces of attraction between them meaning its easy for the particles to overcome this force and escape. You only need a little heat energy (body temperature) to make the perfume evaporate.…read more

Slide 6

SolutionsNail varnish is insoluble in water..The molecules of nail varnish are strongly attracted to each other. The attraction is stronger than the attraction between the nail varnish molecules and the water moleculesThe molecules of water are strongly attracted to each other. This attraction is stronger than the attraction between the water molecules and the nail varnish molecules.Nail varnish is soluble in acetone(nail varnish remover) ...The attraction between the acetone molecules and the nail varnish molecules is stronger than the attractions holding the two substances together.…read more